1. Field of the Invention
The present invention generally relates to devices and methods for checking identification of users, an IC card for checking identification of the owner of the card, and a memory medium having program recorded therein for checking identification of a user. The present invention particularly relates to a user-identification check method, a user-identification check device, and a user identification check card, which achieve high security without imposing undue burden on users or on a system. The present invention further relates to a memory medium having a program embodied therein for achieving such a user-identification check device.
2. Description of the Related Art
As a result of an increasing use of computers in the fabric of society, checking a user identification based on a computer system has begun to be widely used in various fields relating to information processing. In the event that the checking of the user identification errs or misuse of the user identification is not prevented, ramifications include not only damages to individuals but also widespread confusion in society. Society demands a technology that achieves higher security in the checking of user identification.
The scheme most widely used for a user identification check is to let a user pick and register a pin code such as defined by 4 digits. When a user identification needs to be checked, the user enters his/her pin code, and a check is made as to whether the entered pin code and the registered pin code match. A match indicates that the user is authorized.
When a pin code is fixed as defined by a series of fixed digits, someone who sees a user entering a pin code may be able to pick up the code. This compromises security.
Further, users tend to select a pin codes that are easy to remember for them, such as a selected portion of their phone number, the date of birth, the home address, etc. Such a tendency increases a chance of someone correctly guessing a user's pin number. This is also a factor in compromising the security.
In order to obviate the drawbacks described above, Japanese Patent Laid-open Application No. 63-170764 teaches a system in which a user registers a formula and a key number. At a time of user-identification check, the system generates a time-dependent variable. A user enters a number that produces the key number when the entered number is inserted into the registered formula. The number entered by the user is compared with a number calculated by the system. If these two numbers match, the user is authorized.
In the user-identification-check system described above, a user registers a formula “x+y” and a key number “z0=7”, for example. When the system presents a time-dependent variable 3 (=x), a user enters 4 (=y) that satisfies the equation “x+y=7”. Entering such a number proves that the user is an authorized user.
The check of user identification as described above can maintain security even when someone sneakily picks up a number that a user enters. This is because the number that the user enters is not a fixed code such as a pin code. This scheme thus provides higher security.
In this scheme, however, a user needs to remember both the registered formula and the key number, and to calculate a required number in his head. This poses a great burden on a part of the user.
Further, the system also bears the burden in that the system needs to store in memory the registered formula and the registered key number for each user. This requires a large memory size.
Accordingly, there is a need for a scheme which can achieve high security without imposing an undue burden on users or on the system.